Three hundred and fifty kilogrammes of explosives killed Rafiq Al-Hariri in the heart of the city he helped rebuild after it was devastated by civil war.

After drinking coffee with friends in downtown Beirut following a session of parliament in which he took part, Al-Hariri's motorcade was ripped apart by a powerful blast that shook the Lebanese capital and left a five-metre deep crater in the seafront corniche, across from the five-star hotels he had taken a leading role in constructing.

The five-time former premier was killed along with at least 14 others, including his bodyguards. His close ally Basil Fuleihan, who was flown to France for treatment, remains in a critical condition.

Al-Hariri had strived to turn his capital into the Middle East's hub, and he will be buried in it as a hero.

More than 135 people were injured in Monday's blast, the most serious since guns fell silent in Beirut in 1990.

Lebanese from all walks of life converged on the home of the 60-year-old Muslim Sunni, known for his moderation and support for co-existence among Lebanon's 18 different religious sects.

"This is a disaster," a veiled old woman shouted as throngs of young men, women and elderly yelled in disbelief.

Inside Al-Hariri's mansion in Beirut's Koreitem district his son, Bahaa, told mourners that "no one should cry."

"Rafiq Al-Hariri is not gone," he said. "His house will not be shut down."

Tens of thousands paid tribute to the former premier at his home, itself a symbol of Beirut's resurrection.

"It is a great loss for Lebanon, for the family, for every Lebanese and for the Arab world. My father served Lebanon all his life and we will keep serving Lebanon like him. I hope justice will be brought to those who committed this crime," Bahaa's brother, Saadeddin, told the press.

In Lebanon's highly sectarian society the former premier was widely seen as a statesman rather than a Muslim leader. He first took office in 1992 on a platform promoting co-existence among Lebanon's sects. His extensive contacts, both Arab and international, ensured a brief spell of prosperity before political squabbling and criticism of his reconstruction plans saw the economy brought to the brink of melt-down.

He left office in 1998 following a power struggle with the Syrian-backed President Emile Lahoud but returned to office following a landslide victory in 2000. The struggle with Lahoud continued intensifying following his government's pledge at the 2002 international donors conference to reform Lebanon's economy and privatise its corruption-ridden public utilities.

Al-Hariri's differences with Lahoud came to a head following the extension of the latter's term in office after parliament had approved a constitutional amendment, under intense Syrian pressure, to allow Lahoud to continue as president for a third term.

In Beirut, which Al-Hariri always called "the bride of cities", mosques were full and the streets of the normally bustling city empty. Schools, stores, banks and offices have closed for three days of mourning and the newly rebuilt downtown, symbol of the city's renaissance, was deserted.

Al-Hariri came to prominence following his leading role in hammering out the Taif Accord which ended the Lebanese civil war. The agreement, adopted in the Saudi city of Taif, called for an initial redeployment of Syrian troops from Lebanon ahead of a full pullout. It also established a power-sharing agreement between Lebanon's various sects. On the eve of his death, Al-Hariri had reaffirmed his commitment to the Taif Accord in statements to the press.

On the day of Al-Hariri's assassination Al-Jazeera broadcast a tape in which a previously unknown Islamist group member claimed responsibility for the attack, citing Al-Hariri's ties with Saudi Arabia as the reason.

Saudi Prince Talal Bin Abdul-Aziz, half brother of King Fahd, quickly cast doubt over the authenticity of the claims by An-Nosra wal Jihad fi Bilad Al-Sham (Victory and Jihad in the Levant).

"I don't believe that what was broadcast about this group is true," the prince said, as he lent his support to calls from Lebanon's opposition for an international enquiry.

"To blame Jihadist and Salafist groups for what happened in Beirut is a complete fabrication," read a statement, attributed to Al-Qaeda, posted on the Internet on Tuesday.

Another previously unknown group, Al-Qaeda Organisation in the Levant, denied Islamists were behind the attack, pointing a finger at Lebanese, Syrian or Israeli intelligence.

Lebanon's Interior Minister Suleiman Franjieh told a news conference a suicide car bomber might have been responsible for the attack.

"It could be that someone was driving the car and it might have been a suicide bomber who blew himself up," said staunchly pro-Syrian Franjieh.